class_docstr: Test various VIIRS-specific composites.
class_docstr_tok: ["Test","various","VIIRS-specific","composites","."]
docstr: Return fake channel 1 data for DNB tests.
docstr_tok: ["Return","fake","channel","1","data","for","DNB","tests","."]
code: def dnb(self, area):
      """Return fake channel 1 data for DNB tests."""
      dnb = np.zeros(area.shape) + 0.25
      dnb[3, :] += 0.25
      dnb[4:, :] += 0.5
      dnb = da.from_array(dnb, chunks=25)
      c01 = xr.DataArray(
          dnb,
          dims=("y", "x"),
          attrs={
              "name": "DNB",
              "area": area,
              "start_time": datetime(2020, 1, 1, 12, 0, 0),
          },
      )
      return c01
  
file_path: satpy/satpy/tests/compositor_tests/test_viirs.py
imports: from datetime import datetime
  import dask.array
  import numpy
  import pytest
  import xarray
  from pyresample.geometry import AreaDefinition
label_desc: Use image node_id 2 for calling the TestVIIRSComposites obj's underlying member method code with example usage: obj.dnb(area) and returns: c01